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Posts tagged “American Beech

Bruce Spanworms Emerging & Mating

11-7-13 winter moth IMG_4880I try not to repeat post topics, but in the past two days the sudden emergence of inch-long, tan moths in the woods has been so dramatic that I couldn’t not mention them. These ghost-like, light tan moths are referred to by entomologists as Bruce Spanworm moths, Operophtera bruceata, named after an entomologist by the name of Mr. Bruce. They are often called Winter Moths, due to the fact that they are one of the latest moths to be seen flying, as well as Hunter Moths, as they share the woods with hunters at this time of year. From October to December Bruce Spanworm moths emerge, mate and lay eggs. While this timing is unusual, it makes sense when you think about it — many birds, their primary predators, have left for their wintering grounds. All the moths you see in the air are males — females are wingless and cannot fly. The females crawl up the trunk or branch of a tree and send out pheromones to attract winged males. After mating, the female lays eggs which hatch in the spring, and the larvae feed on a wide variety of deciduous leaves, favoring Trembling Aspens, Sugar Maples, American Beeches and willows. Periodic outbreaks of these caterpillars can result in heavy defoliation.

NB: “This is easily confused with Operophtera brumata – Winter Moth, which is an introduced species from Europe and an abundant pest in the Northeast. Also easily confused with Autumnal Moth (Epirrita autumnata).” Kent McFarland


Beech Bark Disease

 Anyone familiar with the beautiful, smooth, gray bark of American beech is well aware that the forest landscape is changing, in part due to the disease that is affecting American beeches. Beech bark disease is caused by not one, but two, agents – an insect and a fungus.  The bark of an American beech is initially attacked and altered by the soft-bodied scale insect, Cryptococcus fagisuga, after which it is invaded and killed by fungi, usually Nectria coccinea var. faginata or N. gallegina. This scale insect was accidentally introduced to Nova Scotia around 1890 and since then has spread far and wide, affecting large American beech trees (over 8 inches) the most.  Pale yellow eggs are laid by the yellow female scale insects (there are no males – they reproduce through parthenogenesis) on the bark of beech trees in mid-summer and hatch in the late summer or fall.  Larvae begin to feed on the bark until winter when they transform into a stage that has no legs and is covered with wool-like wax. The white wax secreted by beech scale insects is the first sign of the disease – heavy infestations of beech scale can cover tree trunks with white wax. Serious damage results only after the invasion of the bark by either one of the fungi mentioned, presumably through injuries made by scale feeding activity.

 


Tree Bud Formation

 

Because tree buds tend to swell and increase greatly in size in the spring, this is often the season when we first notice them and assume that this is when trees produce them.  If you look in the axils of leaves on any tree right now, you will see full-size buds that were formed this summer.   These little packages of miniature leaves, branches and sometimes flowers, will remain on trees all winter, tightly closed and often protected from the elements by modified leaves called bud scales.  Come spring, when trees are once again taking up quantities of water, their buds will swell, scales will fall off (leaving bud scale scars), and tiny, pristine leaves will appear.  (Photo is of American beech, Fagus grandifolia, bud.)

 

 


Beechnuts

Birds and mammals that rely on beechnuts as a staple of their diet include black bears, white-tailed deer, fishers, porcupines, wild turkeys, ruffed grouse, wood ducks, tufted titmice, and numerous small rodents, to name but a few.  There is a good reason for this – beechnuts have about the same protein content as corn, but five times the fat content.  Beechnuts also have nearly twice as much crude protein and twice the fat of white oak acorns and about the same fat content as red oak acorns.  Given the number of husks and nuts that are on the forest floor this fall, it appears that this is a good year for beechnut mast, or seed production.  Research has shown that high beechnut production in the fall is correlated with a high percentage of reproducing female black bears in the coming winter.

 


Beechdrops

Beechdrops (Epifagus virginiana) are parasitic plants which obtain nutrients from the American beech tree.  They insert a root-like structure called a haustorium into a beech root, absorbing enough nutrition to sustain themselves and produce flowers between August and October.  Beechdrops belong to a family of plants (Broomrape), all members of which live as root parasites. Being annuals, beechdrops don’t live long enough to damage their host trees. Because they lack chlorophyll and obvious leaves (their leaves are scale-like and pressed flat against their stem), beechdrops are easily overlooked.  Keep an eye on the base of American beech trees for these 5 – 18-inch plants which are flowering right now.